Improved measures are needed of drug abuse patients' environments. Theories of drug abuse relapse suggest that patients' daily social and physical environments may affect treatment outcomes. Historically, however, treatment researchers have focussed more on intraindividual than environmental influences when exploring potential outcome predictors. Measures of environmental constructs, when used, are often lacking in appropriateness for drug treatment populations. Also, the psychometric properties, construct validity, and generalizability of environmental measures across gender and racial/ethnic groups are often unknown. The proposed work will develop new self-report measures for substance abusers in four broad environmental domains: (a) social influences on drug use and abstinence, (b) general level of reinforcement, (c) stressful events and chronic difficulties, and (d) drug availability. These domains are suggested by major theories of drug abuse, including social learning, cognitive-behavioral, and interactive domain models. Subjects will be 400 opioid-dependent patients in four methadone maintenance treatment programs. The work will proceed in three stages: (a) item selection and pretesting (n = 40), psychometric development (n = 240), and validation (n = 120). In the validation stage, hypotheses will be tested linking patients' environments to their use of illicit drugs during treatment and to treatment adherence and retention. Outcomes will be objectively assessed using data from urine toxicology screens and clinic charts. In future work, we will determine generalizability of the new measures to cocaine patients. Findings from this study will advance our understanding of the effects of social context and physical setting on substance abuse and contribute to an expanded, multicausal perspective on this costly societal problem.